Automatic reclosing-circuit-breaker system



0 1,626,495 April 1927' A. E. ANDERSON AUTOMATIC RECLOSING CIRCUIT BREAKER SYSTEM original Filed June 5, 1922 Invent, o1"

His Attorney.

Patented Apr. 2 ""1921.

UNITED STATES ARVID E. ANDERSON, OF SCHENEGTADY, NEW YORK, ASOI GNOR COMPANY, A CORPORATION OF NEW YOB TO GENERAL ELECTRIC AUTOMATIC nncnosmc-omcurr-nnmxnn 'ss's'rmu.

Application filed June 5, 1922, Serial My invention relates to automatic reclosing circuit breaker systems and articularly to such systems in which it circuit breaker is arranged to connect automatically a source 5 of current toe load circuit, which may or may not supplied with current at more "than one point, as soon as the conditions on the loadifcircuit are such that the circuit breaker can he closed without overloading w the source to be connected and the object of my invention is to provide anew end' improved arrangement for accomplishing; I a

' i 'soiirce 7 totheloadcircuit 1, 2 exceeds a this result i In accordance with my invention: Iipr'o- I 1 rule an arrangement whereby the circuit breaker is closecl in response to a predeterinineol voltage across the load circuit, when the load circuit is not supplied with current I at some other point, and in responseto the current which is proportional to the voltage l 'ierence supplied to the load circuit from source of current to be connecteci thereto hr the ciosingf of the circuit breaker when c ioeci circuit is supplieci with current at some cihe point,

section wiil he better understoocl foliowing clescription taken in con i wi h the accompanying (irewing, scope will; he pointed out in the up to the chewing which shows one my invention, e loscl circuit to he suppliecl from two i its 3, end ti, 6 which are con' iuec'teci to the sources of current '3" ancl 8, Te-

ecti'vely. it is obvious, however, that both if it were so desired. The feeder conductor is srrangeii to be con- "ed to the lead conductor 93 icy snysuitable means such as a circuit breaker 9 which say he closed either automatically or menu sil y The feecier ccnoiuctor t is arranged to he connected to the loaol conciuctor 2- V by means of the automatic reclosing circuit breaker i0. The circuit breaker may beef any suitable type The feezier conductors 23 enci 6 are permanently connected to the load conclucfor 1.

T he circuit breaker 10 shown in the drawing comprises a closing coil 11 which, when energized, maintains the circuit breaker in its closed position. When the circuit breaker is closed .an& the load conditions are normal able type and; asshown in provided with a Winding 17 which iscon-- series with the conductors 2 and 4-,

{ minecl value. 7 ."ciose; the ccntncts of then the voltage chop eeoer circuits 'couid' connected to the circuit for the closing coil 11 which no 5ee,oo1. Renewed Kay 2, 19250 the closing, coil 11 is connected across the feeder circuit 3, 4 by means of the contacts 12- of the overload rela 13, auxiliary contacts 1 10f the circuit reeker and one set of contacts of the two-pole single throw switch 15.

The overloadrelay 13 may he of any suitthe drawing is nectecl in series with the conciuctor 4 and is so arranged that the relay opens itsv contacts when the current supplied fromI-the predetermined value. U i The other. set of contacts of thetwo-pole, single throwswitch 15, when closed, conmeets a current limiting means, such use. f

resistor 18, "acros the terminals of the circuit breaker 10 so that when the circuit breaker isv open the resistor'is connected in I The coils of the relays t9 and 20 are connected; to points on the resistor 18 so that the reisys are ccntroiieci hy the current suppliecl to the icacl circuit when the circ hresfher is open, The reisy 19 is so c signeol that it opens contacts snci incintsins them open lens the voitege drop across the resistcr i8 is shove gcrecie'terinmeci value.

- relay 20* 'ciesigneci so that it tices not ciose ccntscts untii the rcitsge'chep ecrcss the resistcr 18 ehowifefs' pre'oietere The roite'gecirnp lreti tc relay 29 is greater lay ll.

iilie rainy 19 controis one energizin circuit for the closing coil "ii cf the circuit breaker when the circuit breaker" is open. The reiey so controls another energizing also" includes the contacts 22 closing relay 24. These energizing circuits wili he hereinafter described in cie'tcilt" in order to prevent energizing circuits for the closing coilli from being closeci untii a predetermined time after the circuit breaker opens, these circuits inciudi e the conwhich operate the re- I tacts 25 etc time relay 26. The circuit for:

the coil of this time relay 26 is arranged to be connected across the feeder conductors 3, 4; by means of the auxiliary contacts 27 of the circuitbreaker when it iso en. Thi's relay may be of any suitable cons motion so that it does not close its contacts until relay 24 is a polarized relay comprising an armature pivotally mounted within a winding 31 connected across the load circuit 1, 2 and between the pairs of polar projec- .tions 32, 32 and 33, 33 having opposite polarities. The armature 30 carries the contact 22 which engages the stationary contact 23 when the relay is in its reclosing position. A restraining means such as a spring 39 tends to maintain the contact 22 out of engagement with thecontact 23. The magnetic structure 34 of the relay may be either permanently magnetized or 'magnetized by a winding which is energized from any suitable source such as the feeder circuit 3, 4. The magnetic structure 34 is magnetized so that the polar projections 32 and 33 are of opposite polarity and are of the same polarity as the ends 37 and 38, respectively, of the armature 30. With such an arrangement, it is apparent that when the contacts 22 and 23 are open the armature 30 tends to move on its pivot in a direction to close its contacts. By adjusting the spring 39 the relay can bemade so that it closes its contacts 22 and 23 when the voltage impressed upon the operating winding 31 is above a predetermined value. The resistance of the operating winding 31 is high so that an excessive current does notflow through it when the circuit breaker is closed and full voltage is impressed upon the load circuit.

The operation of the arrangement shown in the drawing is as follows: When the switch 15 and the circuit breaker 10 are closed and the operating conditions are normal so that, the contacts 12 of the overload relay 13 are closed the circuit breaker is held in its closed position by the energization of the closing coil 11, the holding circuit of which is as follows: from the feeder conductor 3 through the closing coil 11, closed contacts 12 of the overload relay '13, closed auxiliary contacts 14 of the circuit breaker, closed contacts of the switch 15 to the feeder conductor 4. Since the circuit breaker in its closedposition short circuits the resistor 18, the contacts of the relay 19 are closed and the contacts of the relay 20 are opened. The circuit for the closing coil 11 through the contacts-of the relay 19 is open, however, at the contacts 25 of the time relay 26 since the {circuit of the coil of the time relay is open at the open auxiliary contacts 27 of the circuit breaker. The contacts 22 and 23 of the reclosing relay 24 are closed since full potential impressed on the winding 31 which is connected across the load circuit. 1, 2 and 'fullpotential is :impressed on the magnetizing windin 35 which is connected across the supply circuit 3, 4 by means of the contacts 22 and 23, auxiliary contacts 14 and contacts of the switch 15.

In case of an overload or short circuit on the load circuit 1, 2, the overload relay 13 operates and opens its contacts 12. The opening of these contacts opens the normally closed circuit of the closing coil 11 of the circuit breaker 10 so that the circuit breaker opens. The opening of the circuit breaker opens its contacts 14 so that the magnetizing winding 35 of the reclosing relay is deenergized and this relay opens its contacts 22 and 23. The opening of the circuit breaker also closes its auxiliary contacts 27 thereby connecting the coil of the time relay 26 across the feeder circuit 3, 4. The purpose of this relay is to allow the circuit conditions to become stabilized. The plunger of thisrelay begins to rise and after a certain time the contacts 25 of this relay are closed. The opening of the circuit breaker 10 also opens the short circuit around the current limiting resistor 18. This resistor is so designed that it limits the current supplied to the load circuit to a very small value and therefore the overload relay 12 closes its contacts after the circuit breaker opens. The small current flowing through the current limiting resistor 18 produces a voltage drop across the resistor 18 which is an indication of the load conditions. This voltage drop which varies with the current supplied to the load circuit is used to control the reclosing of the circuit breaker when the circuit breaker is open.

It is evident that if the loadcircuit 1, 2 is not supplied with current from some other source the voltage drop across the resistor 18 is a direct indication of the resistance of the load circuit, whereas if the load circuit 1, 2 is supplied from some other source the voltage vdropacross the resistor 18 does not depend solely on the load resistance but has a value depending on the number of other sources and distance between the short circuit or overload and the other sources supplying current to the load circuit and the magnitude of the overload or short circuit. Since the resistance of the current limiting resistor 18 is much greater than the normal full load resistance, it is evident that for a given load resistance the voltage drop across the current limiting resistor 18 is very much greater when the load circuit is not supplied from some other source than when it is supplied from one or more other sources. Therefore, it is evident that when the circuit breaker is open the voltage drop across the resistor 18 is an indication of whether or not the load circuit is supplied with current from some other source.

Let it be assumed that when the circuit breaker 10 opens in response to an overload 'relay to close its contacts.

or short circuit, the load circuit 1, 2 is not supplied with current from some other source. Under these conditions the circuit breaker 9 is 0 on and the voltage drop across the current limiting resistor 18 issubstantially equal to the voltage of the feeder circuit 3,4. Since the relay 19 is preferably arranged to open and close its contacts in response to very small voltage drops across the resistor 18 and the relay 20 is preferably arranged to close its contact when the voltage drop across the resistor 18 is above a predetermined value, usually some value between 60 and 95 per cent of the normal voltage of the feeder 3, 4, the contacts of the relay 19 are opened and the contacts of therelay 20 are closed when the circuit breaker opens. The closing of the contacts of the relay 20 connects the magnetizing winding of the reclosing relay 24 across the feeder circuit 3, 4. As heretofore set forth, the operating winding 31 is connected across the load circuit 1, 2. When the load resistance increases to a predetermined value the voltage impressed upon the o crating winding 31 increases to a value su cient to close the contacts 22 and 23. ,When these contacts close, an energizing circuit is completed for the closing coil 11 of the circuit breaker to close the circuit breaker. This circuit is as follows: fromthe feeder conductor 3 through the closing coil 11 of the circu t breaker, closed'contacts' 12 of the overload relay 18, contacts 22 and 23 of the reclosing relay 2 1, contacts of the relay20, contacts 25 of the time relay 26, contacts of switch 15 to the feeder conductor 4. When the circuit breaker closes it opens its contacts 27 thercby dcenerg'izing the coil of the time relay 26 and closes its contacts 14, thereby completing the holding circuits heretofore traced for the magnetizing coil and for the coil'll so that the circuit breaker is held in its closed position. Since the closing of the circuit breaker 10 short circuits the resistor 18 the coils of the relays 19 and 20 are deenergized.

Let it now be assumed that when the circuit breaker opens, the load circuit 1, 2 is supplied with current from some other source, such, for example, as the source 8. Under these conditions the voltage drop across the current limiting resistor 18 which is equal to the difference between the voltage across the feeder circuit 3, t and the load circuit 1, 2 is not great enough to cause the- If, however,

' the short circuit or overload remains connected to the load circuit the voltage drop across the current limiting .resistoris sulllcient to cause the relay 19 to open its contacts before the time relay 26 closes its contacts 25. Preferably the relay 19 is designed so that its pick-up and drop-out values are as near-the same value as possible. So long as the voltage clilference between the feeder circuit 3, t

is as follows: from the feeder conductor 3 through the closing coil 11, contacts 12 of the overload relay 13, contacts of the relay 19, contacts 25 of the time relay 26, contacts of the switch 15 to the feeder conductor 4.

-When the-circuit breaker 1O closes the resistor 18 is short circuited and the apparatus is restored to its normal condition in the manner heretofore described.

In case the load is entirely disconnected from the load circuit when it is not supplied from some other source and the circuit breaker 10 is open the only current through the resistor 18 is that which flows through the magnetizing winding 35 and since the iesstance of this winding is great the voltage drop across the resistor is very small. Consequently, the contacts of the relay 19 are closed and the contacts of the relay 20 are open so that when the time relay 26 closes its contacts 25 after the circuit breaker has been open a predetermined time, the heretofore described energizing circuit for the closl ing coil 11 of the circuit breaker 10 through contacts of the relay 19 is completed to efi'ect the closing of the circuit breaker in the same manner as above described when the load circuit is supplied from some other source.

By opening the switch 15 the circuit of the closlng coil is interrupted so that the circuit breaker 10 opens and the circuits of the reclosing relay 24 and time relay 26 are interrupted so that the reclosing equipment is rendered inoperative.

While I have shown and described only one embodiment of my invention I do not desire to be limited thereto but seek to cover in the appended claims all those modifica tions and changes that fall within the true spirit and scope of my invention.

What l'clalm as new and desire to secure by Letters Patent of the United States, 13

1. In an automatic reclosing circuit breaker system, the combination with a load circuit adapted to be supplied with current at a-plurality of points, a supply. circuit arranged to be connected to said load circult, a circuit breaker for controlling the connection between said supply circuit and said load circuit, means adapted to connect said load and supply circuits togetherwhen said circuit breaker isopen, and closing means for said circuit breaker, of means operative in response to the voltage across the load circuit when the current supplied to said load circuit from said supply clrcuit is greater than a predetermined value Inc woltage when said circuit breaker is open to effect the operation of said closing means, and means "operative in response to the current supplied to said load circuit from said supply circuit when said circuit breaker is open and said current is less than said first mentioned predetermined value to efi'ect the operation of said closing means.

2. In an automatic reclosing circuit breaker system, the combination with a load circuit adapted to be supplied with current at'a plurality of points, a supply circuit arranged to be connected to said load circuit, a circuit breaker for controlling the connection between said supply circuit and said load circuit, a current limiting device arranged to be connected in series between said supply and load circuits when the circuit breaker is open, and closing means for said circuit breaker, of means operative in response to a predetermined voltage across said load circuit when the current through said current limiting device exceeds a predetermined value to effect the operation of said closing means, and

means operative in response to the current through said current limiting device when said current is less than said first mentioned predetermined value to effect the operation of 'said closing means.

3. In an automatic reclosing circuit breaker system, the combination with aload circuit adapted to be supplied with current at a plurality of points, a supply circuit arranged tobe connected to said load circuit, a circuit breaker for controlling the connection between said load circuit and said supply circuit, and closing means tor said circuit breaker, of means operative in response to the voltage across said load circuit when the voltage diiference between said load circuit and said supply circuit exceeds a predetermined value to effect the operation of said closing means and means operative in response to a predetermined voltage difference between saidload and supply circuits when said first mentioned difierence is less than said predetermined value to efiect the operation of said closing means.

4. In an automatic reclosing circuit breaker system, the combination with aload circuit adapted to be supplied with current at a plurality of points, a supply circuit arranged to be connected to said load circuit, a circuit breaker for controlling the connection between said load circuit and said supply circuit, a current limiting device arranged to be connected in series with said load and supply circuits when said circuit breaker is en, and closing means for said circuit brea er, of'means operative in re-' sponse to a predetermined voltage across said load circuit when the voltage drop across said. cufent l miting device exceeds a predetermined value to efi'ect the operation of said closing means, and means operative 1n response to a predetermined voltage drop across said current limiting device when said first mentioned voltage drop across said current limiting device is less than said predetermined value to effect the operation of said closing means.

5. In an automatic reclosing circuit breaker system, the combination with a load circuit adapted to be supplied with current at a plurality of points, a supply circuit arranged to be connected to said load circuit, a circuit breaker for controlling the connection between said load circuit and said supply. circuit, and closing means for said circuit breaker, of means operative in response to a predetermined voltage across said load circuit when the voltage difierence between said load circuit and said suppl circuit exceeds a predetermined value to e feet the operation of said closing means, means operative in response to a predetermined voltage difierence between said load circuit and said supply circuit if said first mentioned voltage diiierence is less than said first mentioned value to effect the operation of said closing means, and means arranged to prevent said circuit breaker from closing before the elapse or a predetermined time after its opening, 6. In an automatic reclosing circuit breaker system, the combination with a load circuit adapted to-be supplied with current at a plurality of points, a supply circuit arranged to be connected to said load circuit, a circuit breaker for controlling the connection between said load circuit and said supply circuit, a current limiting device arranged to be connected-in series with said load and supply circuits when said circuit breaker is 0 en, and closing means for said circuit brea er, of means operative in respouse to a predetermined voltage across said load circuit when the voltage drop across said current limitin device exceeds a predetermined value to e ect the operation of said closing means, means operative in response to a predetermined voltage drop across said current limiting device w en said first mentioned voltage drop across said current limiting device 1s less than said predetermined value to effect the operation of said closing means, and means arranged to prevent said circuit breaker from closing before "the elapse of a predetermined time after its opening.

7. In an automatic reclosing circuit breaker system, the combination with a load circuit adapted to be supplied with current at a plurality of points, a supply circuit arranged to be connected to said load circuit, a, circuit breaker for controlling the'connec tion between said supply circuit and. said load circuit, and means for closing the circuit breaker, of means res nsive to the'current supplied to said lo circuit from said supply circuit when said circuit breaker is open for controlling the closing of said circuit breaker, means responsive to the voltage across the load circuit for controllin the closing ofsai'd circuit breaker indepen ently of said current responsive means, and means responsive to the. current supplied to said load circuit from said supply circuit when the circuit breaker is open, to revent the closing of the circuit breaker y said volta e responsive meansrwhenthe current sup led to said load circuit is less than a pre etermined value. v

8. In an automatic reclosing circuit breaker system, the combination with a load circuit adapted to be supplied with current at a pluraht of points a su ply circuit arranged to e connected to said load circuit, a circuit breaker for controlling the connection between said supply circuit and said load circuit, a current limiting device arranged to be connected in series between said supply and load circuits when said circuit brea er is open, meansresponsive to. the

voltage drop in said current limiting device or controlling the closing of said circuit breaker, means responsive to the voltage. across the load circuit for controlling the closing of said circuit breaker independently of said volta drop responsive means, and means responsive to the voltage drop in said current limiting device to prevent the closing of the circuitbreaker by said means responsive to the voltageof the load circuit when the difierence between the supply and load circuit voltages is less than a predetermined value. I i

9. In an automatic reclosing circuit breaker system, the combination with a load circuit adapted to be supplied with current at a pluralitgeof points ranged to connected load circuit, a circuit breaker for controlling the connection between said load circuit and said supplycircuit, and acloaing coil adapted when energized to close said circuit breaker,-. of a relay operative in response to a predetermined voltage difl'erence between said load and supply circuits toefiect the energization of said closing coil, a second reiay operative in response to a predetermined volt- I age across said load circuit to effect the energization of said closing coil, and a third relay operative in response to a predetermined voltage difference between said load and supply circuits to render said second relay inoperative to efiect the energization of said closing coil.

' 10. In an automatic reclosin circuit breaker system the combinationwith a load circuit adapted to be suppliedwith current at a plurality of points, a supply circuit arranged to be connected to ear oad circuit,

a su ly circuit arto a circuit breaker for controlling the connection between saidload circuit and said sup-.

ply circuit, and a closing coil adapted when energized to close said circuit breaker, of a relay operative in response to apredetermined voltage difference between said load and supply circuits to effect the energization of said closing coil, a second relay operative'in response to a predetermined voltage across said load circuit to effect the energization of said closing coil, a third relay operative in response to the voltage difference between said load and supply circuits torender said second relay inoperative to effect the energization of said closing coil, and a time relay operative in response to the opening of the circuit breaker and volts age resumption to prevent the energization with said load and supply circuits when said circuit breaker is open, a closing coil for saidcircuit breaker, a holding circuit for said closing coil arranged to be completed when said circuit breaker is'closed, and an overload rela holding circuit when the current supplied from said supply circuit to said load circuit exceeds a predetermined value, of an'energizarranged to interrupt said ing circuit for said closing coil, contacts in said energizing circuit, a relay operative in response to a predetermined voltage drop across said impedance to effect the closing of vsaid contacts, a secondener "zing circuit for said closing coil, two sets 0 contacts in said second energizing circuit, a-relay operative in res use to a. redetermined voltage "across sai load circuit to'eflect the closing of one of said last mentioned sets of contacts,a relay operative in response to a predetermined voltage drop across said impedance to effect the closing of the other one of saidlas t mentioned sets of contacts, other contactsinboth of said energizing circuits, a time relay 12. In an automatic reclosing -circuit adapted to close said other contacts, and a breaker system, two electric circuits, a 'circuit breaker for connecting said circuits together, closing means for said circuit breaker, means responsive to the volta across one of said circuits for efiecting e operation of said closin means, means responsive to a predetermined .difierence'between the voltage of said circuits for efiec'tcuit, a circuit breaker for connecting said circuits together, overload responsive means for efi'ecting the opening of said circuit breaker, means responsive to the voltage across said load circuit for effecting the reclosure of said circuit breaker, means responsive to a predetermined difference between the voltages of said circuits for effecting the reclosure of said circuit breaker, and means controlled by an electric condition of said load'circuit when said circuit breaker is open for selecting which of said voltage responsive relays shall efiect the reclosure of said circuit breaker.

14;. In an automatic reclosing circuit breaker, a supply circuit, a load circuit, a circuit breaker for connecting said circuits together, overload responsive means for eiiecting the opening of said circuit breaker, current limiting means arranged to be connected between said circuits when said circuit breaker is open, means responsive to the voltage across said load circuit for efiecting the reclosure of said circuit breaker, means responsive to a predetermined voltage drop across said current limiting means for effecting the reclosure of said circuit breaker, and means controlled by an electric condition of said load circuit when said circuit breaker is open for selecting which of said two last mentioned means shall efiect the reclosure of said circuit breaker.

In witness whereof, I have hereunto set my hand this first day of June. 1922.

ARVIDE. ANDERSON; 

